KR20080018551A - Method and apparatus for uplink power control in a communication system - Google Patents

Abstract

A method and an apparatus for reverse power control in a communication system are provided to enable a terminal to transmit reverse data by using different transmission power even if the same target PER(Packet Error Rate) is applied to HARQ(Hybrid Automatic Repeat request) traffic and non-HARQ traffic, thereby improving the reliability of a wireless link by using high transmission power for the HARQ traffic while increasing HARQ gain by applying a high target PER to the HARQ traffic. A method for reverse power control in a communication system comprises the following steps of: transmitting a power control offset, which is to be applied to traffic having a characteristic as standard, to a terminal(104)(106); and setting the transmission power of the traffic by using the power control offset in correspondence to the characteristic of the traffic which the terminal wants to transmit(110).

Description

Method and apparatus for reverse power control in communication system {Method And Apparatus for Uplink Power Control In A Communication System}

1 is a flowchart illustrating an example of a power control scheme according to a first scheme of the present invention.

2 is a flowchart illustrating the operation of a terminal performing power control according to the first method of the present invention.

3 is a flowchart illustrating an example of a power control scheme according to a second scheme of the present invention.

4 is a flowchart illustrating the operation of a terminal performing power control according to the second method of the present invention.

The present invention relates to a method and system for controlling reverse power in a communication system, and more particularly, to a method and system for controlling reverse power when a hybrid automatic repeat request (hereinafter referred to as HARQ) is used in a communication system. It is about.

In general, in a cellular communication system, a base station and a terminal perform reverse power control to minimize the influence of interference while maintaining stable radio link performance. For example, the reverse power control in the Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system is a reverse carrier to maintain a constant target packet error rate (hereinafter referred to as "PER") It is performed so as to maintain a carrier-to-interference and noise ratio (CINR). For example, when the reverse target PER is set to a low value, the reliability of the radio link increases, but the reverse CINR value required to maintain the low target PER increases. On the other hand, if the reverse target PER is set to a high value, the reliability of the radio link is reduced, but the reverse CINR value required to maintain the high target PER is reduced.

However, the output of the terminal is changed in accordance with the required change in the reverse CINR value, and thus the amount of reverse interference, capacity, coverage, etc. of the base station is changed. In other words, when the required reverse CINR value is large, the terminal output is increased and the amount of base station reverse interference is increased, resulting in a decrease in reverse coverage and capacity of the base station. On the other hand, when the reverse CINR value is small, the output of the terminal decreases and the amount of base station reverse interference decreases, resulting in an increase in base station reverse coverage and throughput. Therefore, the reliability of the radio link guaranteed by the reverse power control and the reverse capacity and coverage of the base station are in a trade-off relationship with each other.

In addition, the IEEE 802.16e communication system uses the HARQ scheme [in another way] to increase the reliability of the radio link. When the HARQ method is used, even if an error occurs in the transmission and reception of the packet, normal transmission and reception of the packet is possible by retransmitting the error packet. Therefore, when the HARQ method is used, the backward target is higher with a higher target PER than when the HARQ method is not used. Power control can be performed. As such, when the reverse power control is performed at a high target PER, the required reverse CINR value is reduced, and thus, the base station coverage and capacity can be increased by decreasing the transmit power of the terminal. In addition, even when the terminal uses the same transmission power, when the HARQ scheme is used, the terminal may be operated at a higher modulation product coding (MPR), thereby increasing the reverse data rate. At this time, the generated gain will be referred to as HARQ gain.

On the other hand, even when the HARQ scheme is used in the IEEE 802.16e communication system, the HARQ scheme is not used for the management message and some data traffic. Here, the data traffic that does not use the HARQ scheme is an example of real-time data traffic, and the traffic that does not use the HARQ scheme will be referred to as 'non-HARQ traffic'. Therefore, even in the traffic of the same terminal, a situation in which HARQ traffic and non-HARQ traffic are mixed. In the IEEE 802.16e communication system, a power control information element (IE) in an uplink map (UL (uplink) MAP, hereinafter referred to as UL MAP) message for power control of a terminal. , Hereinafter referred to as 'IE'), the power of the corresponding terminal is controlled. The format of the power control IE is shown in Table 1 below.

   Syntex size  Notes UL-MAP_IE () CID 16 bit    UIUC 4 bit    if (UIUC = 15) {       Extended UIUC dependent IE {          Power Control IE {             Extended UIUC 4bits Fast power control = 0x00             Length 4bits Lenth = 0x01             Power control 8bits Signed integer which expresses the change in power level (in 0.25 dB units) that the SS should apply to correct its current transmission power          }       }    } }

As shown in Table 1, since the power control IE is included in the UL MAP message, the power control IE is divided into only a basic connection identifier (CID) included in the UL MAP message.

Meanwhile, in order to increase the HARQ gain in the IEEE 802.16e communication system, a target PER of about 10 to 30% must be used. However, if the non-HARQ scheme is not used, an error generated in the wireless link cannot be recovered, so the IEEE 802.16e communication system performs reverse power control at a target PER of less than 1% for reliability of the wireless link. Doing. Therefore, a mismatch between HARQ traffic and target PER of non-HARQ traffic occurs. That is, when applying a target PER suitable for HARQ traffic, reliability of non-HARQ traffic is not guaranteed, and applying a target PER suitable for non-HARQ traffic cannot guarantee HARQ gain.

However, in the IEEE 802.16e communication system, as described in Table 1, no consideration is given to whether or not to use the HARQ scheme in reverse power control. Therefore, there is a need for a reverse power control scheme considering the use of the HARQ scheme and the case of not using the HARQ scheme.

Accordingly, an object of the present invention [invented to solve the problems of the prior art operated as described above] is to provide a reverse power control method and system in a communication system.

Another object of the present invention is to provide a method and system for performing reverse power control according to whether a HARQ scheme is used in a communication system.

In order to achieve the above object, an embodiment of the present invention provides a reverse power control method in a communication system.

Transmitting a power control offset to the terminal to be applied to traffic having a characteristic as a reference;

And setting the transmission power of the traffic by using the power control offset according to the characteristics of the traffic to be transmitted by the terminal.

Another embodiment of the present invention, in the reverse power control method in a communication system,

Receiving a power control offset to be applied to traffic having a reference characteristic from a base station,

Setting an initial transmit power,

And setting the transmission power of the traffic by using the power control offset corresponding to the characteristics of the traffic to be transmitted.

Another embodiment of the present invention is a reverse power control method in a communication system,

Transmitting power control information to the terminal to be applied to traffic having characteristics as reference;

And setting the transmission power of the traffic by using the power control information corresponding to the characteristic of the traffic to be transmitted by the terminal.

Another embodiment of the present invention is a reverse power control method in a communication system,

Classifying and receiving power control information to be applied to traffic having a reference characteristic from a base station;

And setting the transmission power of the traffic by using the power control information classified according to the characteristics of the traffic to be transmitted.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. Like reference numerals are used to designate like elements even though they are shown in different drawings, and detailed descriptions of related well-known functions or configurations are not required to describe the present invention. If it is determined that it can be blurred, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention proposes a reverse power control method and system in a communication system, for example, an Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system. In particular, the present invention proposes a method and system for performing reverse power control according to whether to use a hybrid automatic repeat request (hereinafter referred to as HARQ) scheme in the IEEE 802.16e communication system. Hereinafter, in describing the present invention, "HARQ traffic" refers to traffic using HARQ scheme, and "non-HARQ traffic" refers to traffic on which HARQ scheme is not used. Here, the non-HARQ traffic may be some traffic such as a management message and real-time traffic data.

Reverse power control in the present invention is implemented as a power control for HARQ traffic and non-HARQ traffic, proposed as the first and second schemes.

First, in the first scheme of the present invention, an arbitrary power control offset value is referred to as an uplink channel descriptor (UCD) for controlling power by dividing the HARQ traffic and the non-HARQ traffic. ), And to control the power of the base station and the terminal by using the power control offset value.

Specifically, in order to perform the reverse power control operation according to the first method of the present invention, a power control offset value between HARQ traffic and non-HARQ traffic is included in the UCD message.

The first scheme may be implemented in the following two embodiments. In the first embodiment, the reverse power control is performed based on a target packet error rate (hereinafter, referred to as 'PER') of HARQ traffic, and the power control offset value is applied to non-HARQ traffic. Suggest a way. Here, the power control offset value for the non-HARQ traffic is defined as a TLV (Type, Length, Value) format as shown in Table 2 below.

Name Type (1 Byte) Length Value Relative power offset for UL non-HARQ burst TBD One  Offset for non-HARQ burst relative to HARQ burst (Unsigned in 0.25 dB unit)

As shown in Table 2, the power control offset is represented by 1 byte, and the Relative power offset for UL non-HARQ burst of the TLV type shown in Table 2 is called an uplink channel descriptor (UCD). It is included in the message).

In addition, in the second embodiment, a reverse power control is performed based on a target PER of non-HARQ traffic, and a power control offset is applied to HARQ traffic. To apply this scheme, the power control offset value for HARQ traffic is defined in a TLV format as shown in Table 3 below.

Name Type (1 Byte) Length Value  Relative power offset for UL HARQ burst TBD One  Offset for HARQ burst relative to non-HARQ burst (Signed in 0.25 dB unit)

As shown in Table 3, the power control offset is represented by 1 byte, and the Relative power offset for UL HARQ burst shown in Table 3 is included in the UCD message.

In the following description, the reverse power control using the first scheme will be described with respect to the reverse power control operation based on the first embodiment.

First, when the UE operates only in the non-HARQ mode without supporting the HARQ mode operation, the reverse power according to the conventional reverse power control scheme generally used in the IEEE 802.16e communication system regardless of the power control offset value. Control is performed, and the base station also performs reverse power control using a target PER value for existing non-HARQ power control.

On the other hand, if the terminal supports HARQ operation and HARQ traffic and non-HARQ traffic are mixed, the power control offset value is reflected in the reverse power control. That is, the base station performs the reverse power control using a target PER higher than the target PER of the non-HARQ to increase the HARQ gain. Subsequently, when the terminal transmits HARQ traffic, the transmission power is determined in the same manner as the conventional reverse power control scheme, but when the terminal transmits non-HARQ traffic, the power is transmitted to the transmission power determined by the conventional reverse power control scheme. Control to amplify and transmit power by a control offset value.

Here, the time point at which the power offset value is applied is as follows. Since the base station opens the HARQ connection (Connection), based on the HARQ traffic, the base station changes the outer loop target PER to, for example, a non-HARQ target PER of less than 1%, for example, HARQ PER of 10 to 30%. Thereafter, the terminal transmits the reverse traffic with the transmission power applying the power control offset to the non-HARQ traffic.

The power control offset value may be determined by the required target PER difference between HARQ traffic and non-HARQ traffic. If the difference between the required target PER of the HARQ traffic and the non-HARQ traffic is large, the difference between the required Carrier to Interference and Noise Ratio (CINR) is also large. The power control offset value is also set large. On the contrary, if the difference between the required target PER of the HARQ traffic and the non-HARQ traffic is small, the difference between the required reverse CINR value is also small and the power control offset value is also set small.

1 is a signal flow diagram illustrating a reverse power control process according to the first method of the present invention.

Referring to FIG. 1, in step 106, the base station 102 transmits a UCD message including a non-HARQ power control offset value (hereinafter referred to as 'E') and a target CINR to the terminal 104. Here, the power control offset value may be determined by the required target PER difference between HARQ traffic and non-HARQ traffic. If the difference between the required target PER of the HARQ traffic and the non-HARQ traffic is large, the difference of the required reverse CINR value also increases, so that the power control offset value is also set large. On the contrary, if the difference between the required target PER of HARQ traffic and the non-HARQ traffic is small, the difference between the required reverse CINR value is also small and the power control offset value is also set small.

If the base station transmits the noise and interference information IE to the terminal 104 in step 108, the terminal 104 sets the initial transmission power. Here, the initial transmission power is a value calculated based on the same target PER regardless of HARQ traffic and non-HARQ traffic in the conventional IEEE 802.16e communication system, it is calculated as Equation 1 below.

P (dbm) = PL (dB) + CINR Target (dB) + NI (dBm) + 10log10 (BW)

Here, PL is Uplink Path Loss, NI is noise and interference PSD, and BW is allocated bandwidth.

In step 112, a network entry process is performed between the base station 102 and the terminal 104.

 In step 114, the terminal 104 transmits power for the non-HARQ uplink burst calculated through Equation 1 to the base station 102. Here, the power for the non-HARQ uplink burst is the same as the conventional scheme.

When the terminal 104 transmits a bandwidth request and uplink transmission power report header message to the base station 102 in step 116, the base station 102 has a non-HARQ target PER of less than 1% in step 118. The power offset A of 104 is calculated. The power offset (A) is a value for amplifying or reducing the transmission power according to a channel situation, and the method for calculating the power offset (A) is a power offset as described in the present invention, that is, a non-HARQ power control offset value. It is different from (E), and since this is not directly related to the present invention, the detailed description thereof will be omitted here.

After transmitting the power control IE including the calculated power offset A to the terminal 104 in step 120, the HARQ connection between the base station 120 and the terminal 122 is opened in step 122. . In step 124, the terminal 104 determines the power for the HARQ uplink burst and transmits it to the base station 102. In this case, the power for the non-HARQ burst is calculated by Equation 2 to which the power offset A is added to Equation 1 below.

P (dbm) = PL (dB) + CINR Target (dB) + NI (dBm) + 10log10 (BW) + A

When the terminal 104 transmits a bandwidth request and uplink transmission power report header message to the base station 102 in step 126, the base station 102 has a non-HARQ target PER of less than 10% in step 128. The power offset B of 104 is calculated. Here, the power offset (B) is also different from the non-HARQ power control offset value (E) in the present invention, which is not directly related to the present invention will be omitted here.

In step 130, the base station 102 transmits the power control IE including the calculated power offset B to the terminal 104. In step 132, the terminal 104 supplies power for the non-HARQ uplink burst. Determine and transmit to the base station 102. In this case, since the HARQ connection is open, the non-HARQ power control offset E is considered according to the present invention. That is, the power for the non-HARQ burst is calculated by Equation 3 wherein the power offset B and E are added to Equation 1.

P (dbm) = PL (dB) + CINR Target (dB) + NI (dBm) + 10log10 (BW) + B + E

When the terminal 104 transmits a bandwidth request and uplink transmission power report header message to the base station 102 in step 134, the base station 102 has a non-HARQ target PER of less than 10% in step 136. Calculate the power offset C of 104.

In step 138, the base station 102 transmits the calculated power control IE including the B to the terminal 104, and in step 140, the terminal 104 determines the power for the HARQ uplink burst and the base station ( 102). Here, the power for the HARQ burst is calculated by Equation 4 to which the power offset C is added to Equation 1. Here, the power offset (C) is also different from the non-HARQ power control offset value (E) in the present invention, which is not directly related to the present invention, a detailed description thereof will be omitted here.

P (dbm) = PL (dB) + CINR Target (dB) + NI (dBm) + 10log10 (BW) + C

In step 142, if a bandwidth request and uplink transmission power report header message is transmitted to the base station 102, in step 144, the base station 102 has a non-HARQ target PER of less than 10% and offsets the power of the terminal 104. Calculate (D).

In step 146, the base station 102 transmits the power control IE including the calculated power offset D to the terminal 104. In step 148, the terminal 104 determines the power for the HARQ uplink burst. The base station 102 transmits. Herein, the power offset (D) is also different from the non-HARQ power control offset value (E) in the present invention, which is not directly related to the present invention, and thus the detailed description thereof will be omitted here. The power for the HARQ burst is calculated by Equation 5 below, wherein E and D are added to Equation 1.

P (dbm) = PL (dB) + CINR Target (dB) + NI (dBm) + 10log10 (BW) + D + E

As described above, the base station 102 sets initial transmission power regardless of HARQ and non-HARQ through Equation (1). Thereafter, when the HARQ connection is opened, the base station 104 calculates the HARQ traffic by adding the power control value calculated according to the channel condition to the initial transmission power value to Equation 1. On the other hand, for non-HARQ traffic, a non-HARQ power control offset is calculated by adding the initial transmit power value to a power control value calculated according to channel conditions, thereby obtaining a lower backward error through amplified transmit power than before. .

2 is a flowchart illustrating an operation of a terminal that performs power control according to the first method of the present invention.

Referring to FIG. 2, in step 202, when the UE 104 receives a UCD message including a target CINR and a non-HARQ power control offset (N) from a base station, in step 204, initial transmission power is obtained using Equation 1 above. Set.

In step 206, the terminal 104 sets its power control offset (Offset per SS) to '0', and in step 208 receives the power control IE from the base station. Here, the power control IE includes a power offset (Offset per SS_new) for amplifying or reducing the transmission power according to the channel condition. In step 210, the terminal 104 changes the offset per SS set to '0' to Offset per SS_new received from the power control IE, and in step 212, the terminal 104 checks whether the HARQ connection is open. .

If the HARQ connection is not open as a result of the check, step 216 is performed. In step 216, the terminal 104 sets transmission power to Equation 1 plus Offset per SS_new received in step 210.

If the HARQ connection is opened as a result of the check, in step 214, the terminal 104 determines whether a HARQ burst exists. If there is a HARQ burst as a result of the determination, in step 220, the terminal 104 sets the transmission power to Equation 1 plus Offset per SS_new received in step 210. If there is no HARQ burst as a result of the determination, in step 218, the terminal 104 amplifies and sets the transmission power to a value obtained by adding N set in step 202 to the set transmission power value.

As described above, the UE according to the first embodiment of the present invention amplifies and transmits power by a non-HARQ power control offset value (E) for the non-HARQ burst while operating in the HARQ mode. Thus, backward error does not increase even for non-HARQ bursts.

Next, a second method of the present invention will be described.

In the current 802.16e system standard, the UE informs the power control feedback information through the power control IE. That is, the power control IE informs the information using only a basic CID. Therefore, a terminal having two or more traffics having different target PERs can receive only one of the power control information, thereby causing either traffic to suffer. Therefore, in the present invention, a primary CID is added to the CID field of the power control IE in the 802.16e system, and a different type of traffic power control information is loaded on each of the primary CIDs. Specifically, the basic CID defines power control feedback information for non-HARQ traffic, and the primary CID is defined to inform power control feedback information of HARQ traffic, respectively. Thereafter, the terminal uses the CID field as power control feedback information referred to when UL transmission of a burst of the corresponding traffic.

3 is an example illustrating a power control method procedure according to the second method of the present invention.

Referring to FIG. 3, in step 306, the base station 302 transmits a UCD message including the target CINR to the terminal 304.

If the base station transmits the noise and interference information IE to the terminal 304 in step 308, the terminal 304 sets initial transmission power in step 310. In this case, the initial transmission power is a value calculated based on the same target PER regardless of HARQ and non-HARQ traffic in the conventional technology, and is calculated as in Equation 1 above.

In step 312, a network entry process is performed between the base station 302 and the terminal 304.

In step 314, the terminal 304 transmits the power for the non-HARQ uplink burst calculated through Equation 1 to the base station 302. Here, the power for the non-HARQ uplink burst is the same as the conventional scheme.

When the terminal 304 transmits a bandwidth request and uplink transmission power report header message to the base station 302 in step 316, the base station 302 has a non-HARQ target PER of less than 1% in step 318. Compute a power offset A of 104. The power offset A is a value for amplifying or reducing a transmission power according to a channel condition. In the present specification, a detailed description thereof will be omitted since it is not directly related to the present invention.

In step 320, the base station 302 transmits a power control IE to the terminal 304. In this case, the power control IE includes the calculated A and a basic CID representing target PER information of non-HARQ traffic.

In step 322, the HARQ connection between the base station 320 and the terminal 322 is opened. Since the terminal 304 did not receive the power control information for the HARQ uplink burst in step 324, the transmission power of the HARQ uplink burst is set to the initial transmit power determined in step 310 to the base station 302. send.

When the terminal 304 transmits a bandwidth request and uplink transmission power report header message to the base station 302 in step 326, the base station 102 has a HARQ target PER of less than 10% in step 328. In step 330, the base station 302 transmits the power control IE including the calculated B to the terminal 304. Here, since the method of calculating the power offset (B) is not directly related to the present invention, a detailed description thereof will be omitted.

 In step 332, the terminal 304 determines the power for the non-HARQ uplink burst and transmits it to the base station 302. In this case, since the HARQ connection is open, A, which is power control information of the received basic CID, is considered according to the present invention. That is, the power for the HARQ burst is calculated by Equation 2 wherein A is added to Equation 1.

When the terminal 304 transmits a bandwidth request and uplink transmission power report header message to the base station 302 in step 334, the base station 302 has a non-HARQ target PER of less than 1% in step 336. The power offset C of 304 is calculated. Thereafter, in step 338, the base station 302 transmits the power control IE including the calculated C and the basic CID to the terminal 304. Here, since the method of calculating the power offset (C) is not directly related to the present invention, a detailed description thereof will be omitted.

In step 340, the terminal 304 determines the power for the HARQ uplink burst and transmits it to the base station 302. Here, the power for the HARQ burst is considered B, which is power control information of the received primary CID according to the present invention. That is, Equation 3 is added to Equation 1 plus B.

If the terminal 304 transmits a bandwidth request and uplink transmission power report header message to the base station 102 in step 342, the base station 302 has a non-HARQ target PER of less than 10% in step 344. Calculate the power offset D of 104. Here, since the method of calculating the power offset (D) is not directly related to the present invention, a detailed description thereof will be omitted. In step 346, the base station 302 transmits the power control IE including the calculated D to the terminal 304.

 In step 348, the terminal 304 determines the power for the non-HARQ uplink burst and transmits it to the base station 302. Herein, the power for the non-HARQ burst is calculated by Equation 4 which adds the C through the basic CID received in step 338 to Equation 1 below.

As described above, the base station 302 according to the second room performs power control using different target PERs for HARQ and non-HARQ traffic, and at this time, the power control values are different from each other. CID and primary CID) to the terminal through a power control IE.

4 is a flowchart illustrating an operation of a terminal performing power control according to the second method of the present invention.

Referring to FIG. 4, when the base station 302 receives the UCD message including the target CINR in step 402, the base station 302 sets initial transmission power using Equation 1 in step 404.

In step 406, the terminal 304 sets the HARQ power control offset (Offset per SS_HARQ) to '0' and sets the HARQ power control offset (SS_HARQ) to '0', respectively. Thereafter, in step 408, the power control IE is received from the base station. Here, the power control IE includes a primary CID and a basic CID, which mean power control feedback information according to the type of traffic. This means that the base station performs power control using a corresponding target PER for each of HARQ traffic and non-HARQ traffic, and then transmits it to the terminal 304 through the CID. Specifically, the primary CID means power control information (Offset per SS_HARQ_new) of HARQ traffic, and the basic CID means power control information (Offset per SS_nHARQ_new) of non-HARQ traffic.

 In step 410, the terminal 304 checks whether the CID received through the power control ID is a basic CID or a primary CID. If the check result is a basic CID, in step 412, the terminal 304 changes the Offset per SS set to '0' to Offset per SS_new_nHARQ received from the power control IE and proceeds to step 416. 21

If the check result is the primary CID, in step 414, the terminal 304 changes the offset per SS set to '0' to Offset per SS_new_nHARQ received from the power control IE, and then proceeds to step 416.

In step 416, the terminal 304 determines whether the HARQ burst exists, and if the HARQ burst does not exist as a result of the determination, transmit power is equal to Equation 1 plus Offset per SS_nHARQ_new set in step 412. Set it.

If there is a HARQ burst as a result of the determination, in step 420, the terminal 304 sets the transmission power to Equation 1 plus Offset per SS_HARQ_new received in step 414.

 As described above, the terminal according to the second aspect of the present invention, by looking at the CID of the power control IE received from the base station, and performs the power control independently by separating the HARQ and non-HARQ traffic according to the CID.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention is to solve the target PER mismatch between HARQ traffic and non-HARQ traffic that may occur in the reverse power control when HARQ is applied, HARQ traffic and non-HARQ traffic is the same target PER when applying the present invention Even if the UE is applied, the reverse data is transmitted using different transmission powers. Therefore, the HARQ traffic is increased by applying a high target PER to HARQ traffic, and at the same time, the reliability of the radio link can be enhanced by using a higher transmission power than that of HARQ traffic for non-HARQ traffic.

Specifically, since the first scheme performs power control using a fixed offset value for non-HARQ traffic, it may be less effective in performing precise power control, but it can be applied without major changes in the existing 802.16e system implementation. There is an advantage. In addition, there is an effect that can be applied while minimizing the increase of additional signaling overhead.

Next, since the second scheme performs power control independently for non-HARQ and HARQ traffic, signaling overhead may exist, but there is an advantage that detailed power control is possible than the first scheme.

Claims (22)

In the reverse power control method in a communication system, Transmitting a power control offset to the terminal to be applied to traffic having a characteristic as a reference; And setting the transmission power of the traffic by using the power control offset according to the characteristics of the traffic to be transmitted by the terminal. The method according to claim 1, wherein the characteristic as the reference is Any one of a first characteristic of applying a hybrid automatic repeat request (HARQ) scheme to the traffic and a second characteristic of not applying the HARQ scheme to the traffic (non-HARQ), If the reference characteristic is a first characteristic, the power control offset is a power control offset of HARQ traffic, And the power offset is a power control offset of non-HARQ traffic when the reference characteristic is a second characteristic. The method of claim 2, wherein the setting of the transmission power of the traffic comprises: Receiving an initial transmission power set from the terminal; Determining whether the characteristic of traffic to be transmitted by the terminal corresponds to one of the two characteristics when the characteristic as the reference characteristic is the first characteristic; If the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the second characteristic, determining whether the HARQ connection is open; And if the HARQ connection is open, the transmission power of the traffic is set to a value obtained by adding the power offset to the initial transmission power. The initial transmission power of claim 3, wherein the initial transmission power is set as the transmission power of the traffic if the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the first characteristic, or if the HARQ connection is open. Reverse power control method characterized in that. The method of claim 2, wherein the setting of the transmission power of the traffic comprises: Receiving an initial transmission power set from the terminal; Determining whether the characteristic of traffic to be transmitted by the terminal corresponds to any one of the two characteristics when the characteristic as the reference characteristic is the second characteristic; Determining whether the HARQ connection is open when the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the first characteristic; And if the HARQ connection is open, the transmission power of the traffic is set to a value obtained by subtracting the power offset from the initial transmission power. 4. The method of claim 3, wherein the determination results that the initial transmission power is set to the transmission power of the traffic if the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the second characteristic, or if the HARQ connection is opened as a result of the confirmation. Reverse power control method characterized in that. The method of claim 2, wherein the power control offset value, And the target packet error rate required for each of the traffic having the first characteristic and the second characteristic. In the reverse power control method in a communication system, Receiving a power control offset to be applied to traffic having a reference characteristic from a base station, Setting an initial transmit power, And setting transmission power of the traffic by using the power control offset in accordance with a characteristic of traffic to be transmitted. The method according to claim 8, wherein the characteristic as the reference is Any one of a first characteristic of applying a hybrid automatic repeat request (HARQ) scheme to the traffic and a second characteristic of not applying the HARQ scheme to the traffic (non-HARQ), If the reference characteristic is a first characteristic, the power control offset is a power control offset of HARQ traffic, And the power offset is a power control offset of non-HARQ traffic when the reference characteristic is a second characteristic. The method of claim 9, wherein the setting of the transmission power of the traffic comprises: Determining whether the characteristic of the traffic to be transmitted by the terminal corresponds to one of the two characteristics when the characteristic as the reference is the first characteristic; If the characteristic of the traffic to be transmitted is the traffic corresponding to the second characteristic, determining whether the HARQ connection is open; And if the HARQ connection is open, setting the transmission power of the traffic to a value obtained by adding the power offset to the initial transmission power. 12. The method of claim 10, wherein if the characteristic of the traffic that the terminal intends to transmit is traffic corresponding to the first characteristic, or if the HARQ connection is open, the initial transmission power is set to the transmission power of the traffic. Reverse power control method further comprising the step of. The method of claim 9, wherein the setting of the transmission power of the traffic comprises: Receiving an initial transmission power set from the terminal; Determining whether the characteristic of traffic to be transmitted by the terminal corresponds to any one of the two characteristics when the characteristic as the reference characteristic is the second characteristic; Determining whether the HARQ connection is open when the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the first characteristic; And if the HARQ connection is open, setting the transmission power of the traffic to a value obtained by subtracting the power offset from the initial transmission power. 13. The method of claim 12, wherein the determination results that the initial transmission power is set as the transmission power of the traffic if the characteristic of the traffic to be transmitted by the terminal is the traffic corresponding to the second characteristic, or if the HARQ connection is opened as a result of the confirmation. Reverse power control method characterized in that. The method of claim 8, wherein the power control offset value, And the target packet error rate required for each of the traffic having the first characteristic and the second characteristic. In the reverse power control method in a communication system, Transmitting power control information to the terminal to be applied to traffic having characteristics as reference; And setting the transmission power of the traffic by using the power control information in accordance with the characteristics of the traffic to be transmitted by the terminal. The method according to claim 15, wherein the characteristic as the reference is Any one of a first characteristic of applying a hybrid automatic repeat request (HARQ) scheme to the traffic and a second characteristic of not applying the HARQ scheme to the traffic (non-HARQ), When the reference characteristic is a first characteristic, the power control information is power control information of HARQ traffic set according to a target packet error rate (PER) of HARQ traffic. And the power information is power control information of the non-HARQ traffic according to the PER of the non-HARQ traffic when the reference characteristic is the second characteristic. The method of claim 16, wherein the power control information, And if the power control information of the traffic of the first characteristic is set to the primary connection identifier, and if the power control information of the traffic of the second characteristic is set to the basic connection identifier. 17. The method of claim 16, wherein the primary connection identifier and the basic connection identifier are included in a power control element and transmitted to the terminal. In the reverse power control method in a communication system, Classifying and receiving power control information to be applied to traffic having a reference characteristic from a base station; And setting transmission power of the traffic by using the power control information classified according to the characteristics of the traffic to be transmitted. 20. The method of claim 19, wherein the reference characteristic is Any one of a first characteristic of applying a hybrid automatic repeat request (HARQ) scheme to the traffic and a second characteristic of not applying the HARQ scheme to the traffic (non-HARQ), When the reference characteristic is a first characteristic, the power control information is power control information of HARQ traffic set according to a target packet error rate (PER) of HARQ traffic. And the power information is power control information of the non-HARQ traffic according to the PER of the non-HARQ traffic when the reference characteristic is the second characteristic. The method of claim 20, wherein the power control information, And if the power control information of the traffic of the first characteristic is set to the primary connection identifier, and if the power control information of the traffic of the second characteristic is set to the basic connection identifier. 22. The method of claim 21, wherein the primary connection identifier and the basic connection identifier are included in a power control element and transmitted to the terminal.

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